Removable fin system

ABSTRACT

A pivotal fin system, for use with an aquafoil, such as surfboards, body boards, wave skis, sail boards, wake boards and the like, comprising a pot ( 3 ) and a fin ( 2 ), having a tab ( 18 ) extending from the base ( 17 ) of the fin ( 2 ). The pot ( 3 ) has a central slot ( 11 ) and is mounted in the board ( 23 ) with the opening of the central slot ( 11 ) flush with the board ( 23 ). The slot ( 11 ) has a releasable locking means ( 6  &amp;  7 ) therein, and the tab ( 18 ) has a connection means ( 21  &amp;  22 ), which is releasably engaged by locking means ( 6  &amp;  7 ). Preferably the releasable locking means ( 6  &amp;  7 ) is a substantially c-shaped clamp, and the connection means ( 21  &amp;  22 ) has a recess or recesses ( 22 ) behind a bulbous extension ( 21 ), which is engaged in the c-shaped clamp, with arms ( 5 ) of the c-shaped clamp engaging in the recess or recesses ( 22 ).

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a removable fin system, and inparticularly to removable fin system for an aquafoil, such assurfboards, body boards, wave skis, sail boards, wake boards and thelike.

2. Background and Prior Art

It is known to produce a releasable fin for surfboards and the like,such that the fin can be replaced if damaged, or conditions of the waterchanges, e.g. different wave conditions. In the prior art, such asAustralian patent no. 665804, some of the replaceable fins are affixedto the boards by screws, which requires tools to remove and replace thefin, or by a cam, as in Australian patent 718340. In other situationsthe replaceable fins have a tab, which fits into a slot cut into theboard and has backwardly facing barbed sides, which lock into the coreof the board to resist removal.

Another prior art replaceable fin is shown in Australian Patent no.693962, in which the replaceable fin system has a pot fitted into theboard. The pot has a central slot with reversed tapered walls flaringfrom its opening to its base within the board. The fin has a tab portionto fit into the central slot. The tab has tapered sides, complementaryto the flared central slot, which at least one vertically longitudinallyextending cutout in the tab to form wings, which are forced together toallow the tab to fit within the slot opening.

Whilst this system is acceptable, it has been found that the reversetaper on the wings of the tab, allows the tab to wiggle partway out ofthe slot in certain conditions of high stress, which greatly reduces theefficiency of the fin.

SUMMARY OF THE INVENTION

The present invention seeks to ameliorate the above disadvantages byproviding a replaceable fin system for an aquafoil, such as surfboards,body boards, wave skis, sail boards, wake boards and the like,comprising:

a pot having a slot therein, and adapted to be fitted into the surfaceof the aquafoil;

a first connection means extending into said slot;

a fin having a tab which fits within said slot, and a second connectionmeans located on said tab, which releaseably engages with said firstconnection means to retain said tab in said slot.

In one embodiment the wall or walls of the slot are substantiallyparallel

In another form, the invention comprises a replaceable fin system for anaquafoil, such as surfboards, body boards, wave skis, sail boards, wakeboards and the like, comprising:

a pot having a slot, therein, and adapted to be fitted into the surfaceof the aquafoil;

a fin having a leading edge, a trailing edge, a bottom surface and a tabextending from the bottom surface away from the fin and extending alongthe bottom surface from the leading edge to a point intermediate theleading and trailing edges of the fin, said tab fitting within saidslot; and

a connection means located on said tab, which releaseably engages insaid slot.

In one embodiment, the second connection means is formed integrally withsaid pot.

In a further embodiment, the second connection means fits into the baseof the slot where it is held against the base of the pot.

In a further form the invention comprise a method of inserting a pot fora replaceable fin system for an aquafoil, such as surfboards, bodyboards, wave skis, sail boards, wake boards and the like, as describedbefore comprising the steps of:

marking aligning points on the aquafoil, for the fin position;

positioning a first jig having registration points and a central cutout,such that the registration points align with the registration markers onthe aquafoil and securing said first jig in position;

routing out a cavity bounded by the periphery of the central cavity ofthe first jig;

attaching one of said pots to a setup jig and positioning said setup jigon said first jig such that said pot is positioned within said cavity;

introducing a setting compound into said cavity around said pot andallowing said setting compound to set to secure said pot in said cavity;and

removing said setup jig from said pot.

Preferably the setting compound is a resin.

Preferably the registration markers are cross hair lines, and theopening of the pot cavity is bevelled.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described with reference to theaccompanying drawings in which:

FIG. 1 illustrates a bottom exploded perspective view of a fin systemaccording to one embodiment of the present invention;

FIG. 2 illustrates a top exploded perspective view of the fin systemshow in FIG. 1;

FIG. 3 illustrates a sectional view of the fin system according to FIGS.1 & 2, with the components connected;

FIG. 4 illustrates schematically, stages in aligning the first jig onthe surfboard;

FIG. 5 illustrates the stage of affixing the setup jig to a pot of thefin system as shown in FIGS. 1 to 3 of the accompanying drawings;

FIG. 6 illustrates schematically the positioning of the pot of the finsystem as shown in FIGS. 1 to 3 of the accompanying drawings into theboard cavity;

FIG. 7 illustrates schematically a further stage in affixing the pot ofthe fin system as shown in FIGS. 1 to 3 of the accompanying drawingsinto the board cavity;

FIG. 8 illustrates schematically the affixing of a fin into the finsystem according to the embodiment shown in FIGS. 1 to 3 of theaccompanying drawings;

FIG. 9 illustrates a top exploded perspective view of a fin systemaccording to another embodiment of the present invention, with a cutaway view of the pot; and

FIG. 10 illustrates a sectional view of the fin system according to FIG.9, with the components connected.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As shown in FIGS. 1, 2 and 3, a replaceable fin system according to oneembodiment of the present invention comprises a clip (1), a fin (2) anda pot (3). The clip (1) comprises a base (4) having two arms (5),terminating in free ends (6), forming a c-shaped cavity (7)therebetween. The clip (1) also has two shoulders (8) extendingoutwardly from the base (4) beyond the arms (5).

The pot (3) comprises a central body (9) having an array of outwardlyextending wings (10) on each side thereof. A longitudinally extendingclosed slot (11) extends into the central body (9) and a cutout (12) isformed in the base (13) of the pot (3) to receive the clip (1). Wherebythe clip (1) extends into the slot (11) with the shoulders (8) of theclip (1) abutting against the recessed shoulders (14) of the cutout(12).

The fin (2) comprises a leading edge (15), a trailing edge (16) and abase (17), with a tab (18) extending therefrom. In the describedembodiment, the tab (18) starts at the leading edge (15) of fin andextends along the base (17) to approximately mid point of the base (17).The tab (18) has two end portions (19), which are of substantially thesame width as the width of the slot (11) and has an intermediate section(20) an outer rail (21) with two recesses (22) located behind the rail(21).

Therefore when the clip (1) is in position in said cutout (12), and thetab (18) of the fin (2) is pushed into the slot (11), the rail (21)forces the free ends (6) of the arms (5) of the clip (1) apart and matesin the c-shaped cavity (7) of clip (1), with the free ends (6) of thearms (5) engaging behind the rail (21) in the recesses (22), as shown inFIG. 3, to exert vertical pressure on the rail (21), drawing the fin (2)downwardly into the slot (11). In one embodiment, the arms (5) provide afirst connection means and the rail (21) provides a second connectionmeans.

The fin system can be affixed to board as shown in FIGS. 4 to 8, whereinthe pot (3) and clip (1) are embedded in the board (23).

As shown in FIG. 4, two reference points (24) are marked on the board(23) for each fin (2) position. A suitable adhesive in the case a doublesided adhesive tape (25) is applied to the board (23). The jig (26) ispositioned on the adhesive by aligning the respective reference lines(27) with the reference points (24) on the board. (23). With the backcentral fin the middle cross hairs (28) are used to align with thereference points (24), while with the forward angled fins the respectiveinside cross hairs (29) are used to align with the reference points(24).

The jig (26) is then secured by the adhesive tape (25) and a router isused to follow the periphery of the central opening (30) of the jig (26)to form a cavity (31) in the board (23) to receive the pot (3).Preferably the edges of the cavity are bevelled or under cut.

As shown in FIG. 5, a set up jig (32) is inserted into the slot (11) andthe pot (3) placed in the cavity (31) in the board (23), with the set upjig (32) resting upon the jig (26), with part of the central body (9)standing proud of the cavity (31). A suitable setting compound, such asa resin mixture, is poured to fill the cavity (31) around the pot (3).The resin is allowed to cure for a suitable time, and the set up jig(32) and the jig (26) are removed.

Then as shown in FIG. 7, the central body (9) of the pot (3), standingproud of the cavity (31) and any additional resin is sanded away, to asmooth finish, leaving the slot (11) substantially flush with thesurface of the board (23). The fin (2) is simple affixed to the board(23) by pushing the tab (18) into the slot (11), where the tab (18)locks into the clip (1) as described previously.

In the prior art, fins have a tab adjacent each end of the base, or afull length tab, both of which prevents pivoting of the trailing edge ofthe fin, or as shown in Australian Patent no. 693962, a centrallylocated tab, which does not allow for full pivoting of the trailing edgeof the fin. In the embodiments of the present invention, by positioningthe tab (18) at the leading edge (15) of the fin (2) and having itfinish at approximately the mid point of the base (17) of the fin (2),the trailing edge is free of the board (23), and can pivot, to a greaterdegree, under the hydraulic forces to reduce drag and cavitation andincrease the power of the fin (2). However the tab (18) can finish anysuitable distance along the fin provided that the tab starts at theleading edge (15) of the fin (2).

A further embodiment of the fin system is shown in FIGS. 9 & 10 in whichthe pot (3) has locking arms (5), which operate in the same manner toengage the rail (21) and engage in the recesses (22) as the arms (5) ofthe clip (1) described previously.

Further the shape of the rail and the form of the arms and therespective recesses can be any suitable shape. Further any suitable maleand female connections involving a positive locking fit as compared to africtional fit can be used to connect the tab of the fin in the slot ofthe pot. Further the male component could be in the slot with the femalecomponent on the fin.

The pot can be made of any suitable polymer material, such aspolycarbonate with a 20% glass fill; the clip could be made from anysuitable polymer, such as nylon 66, acetyl or polyethylene orpolypropylene or an elastomer; the fin could be made from any suitablematerial.

It should be obvious to people skilled in the art that alterations andmodifications could be made to the above described embodiment withoutdeparting from the scope and the spirit of the present invention.

1. A replaceable fin system for an aquafoil, comprising: a pot having aslot therein and adapted to be fitted into the surface of the aquafoil;a first connection means extending into said slot; a fin having aleading edge, a trailing edge, a base, a tab extending from the baseaway from the fin and adapted to fit within said slot, said tabextending along the base of the fin from adjacent the leading edge toend at a point intermediate the leading and trailing edges, wherein aportion of the fin adjacent the trailing edge is adapted to remain freeof the acquafoil to pivot dynamically in response to differingconditions; and a second connection means located on said tab, whichreleasably engages with said first connection means to retain said tabin said slot wherein said first connection means comprises two opposedarms, and the second connection means comprises a bulbous projectionlocated on a neck of the tab and the two arms engage the neck behind thebulbous projection to abut against the bulbous projection to resist thevertical movement of the fin out of the slot, wherein the arms extendlongitudinally along the slot and form a substantially c-shaped clamp incross section and the bulbous projection is a rail extendinglongitudinally along the tab, with the neck being a longitudinallyextending recess or recesses located between the rail and the base ofthe fin.
 2. A fin system according to claim 1 wherein the slot has itswall or walls substantially parallel.
 3. A fin system according to claim1, wherein the first connection means is formed integrally with saidpot.
 4. A fin system according to claim 1, wherein the first connectionmeans fits into a cutout in the base of the pot where it is held againstthe base of the pot and extends into the slot.
 5. A fin system accordingto claim 1, wherein the rail and the recess or recesses are locatedintermediate two end portions of the tab, which are of substantially thesame width as the width of the slot.
 6. A replaceable fin system for anaquafoil, comprising: a pot having a body, having a top, a base with anopening therein and an array of sideway extending wings, a slot in thebody open to the top, said pot being adapted to be fitted into thesurface of the aquafoil; a clip adapted to be located in a cutout in thebase of the body, where the clip is held against the base of the pot andextends into said slot; said clip having two opposed arms, extendinglongitudinally along the slot, which form a substantially c-shaped clampin cross section, with a substantially cylindrical central cavity; a finhaving a leading edge, a trailing edge, a base, a tab extending from thebase away from the fin and being adapted to fit within said slot, saidtab extending along the base of the fin from adjacent the leading edgeto a point intermediate the leading and trailing edges; and a railextending longitudinally along at least the central portion of the tab,with a recess or recesses located between the rail and the base of thefin, wherein when said tab is pushed into said slot, the two arms of theclip are forced aside and lock into the recesses or recess holding therail within the substantially cylindrical central cavity of the c-shapedclamp, to resist the movement of the fin out of the slot.
 7. A finsystem according to claim 6 wherein the slot has its wall or wallssubstantially parallel.
 8. A fin system according to claim 7 wherein therail and the recess is located intermediate two end portions of the tabwhich are of substantially the same width as the width of the slot.
 9. Afin system according to claim 6 wherein the tab extends along the bottomsurface of the fin from the leading edge to approximately the mid pointbetween the leading and trailing edges of the fin.
 10. A replaceable finsystem for an aquafoil, comprising: a pot having a body, having a top, abase with an opening therein and an array of sideway extending wings, aslot in the body open to the top, said pot being adapted to be fittedinto the surface of the aquafoil; a clip adapted to be located in acutout in the base of the body, where the clip is held against the baseof the pot and extends into said slot, said clip having two opposedarms, extending longitudinally along the slot, which form asubstantially c-shaped clamp in cross section, with a substantiallycylindrical central cavity; a fin having a leading edge, a trailingedge, a base, a tab extending from the base away from the fin, said tabbeing adapted to fit within said slot; and a rail extendinglongitudinally along at least the central portion of the tab, with arecess or recesses located between the rail and the base of the fin,wherein when said tab is pushed into said slot, the two arms of the clipare forced aside and lock into the recesses or recess holding the railwithin the substantially cylindrical central cavity of the c-shapedclamp, to resist the movement of the fin out of the slot and therebyreleasably retain the fin to the aquafoil without threaded or additionalfastening means.
 11. A fin system according to claim 10 wherein the slothas its wall or walls substantially parallel.
 12. A fin system accordingto claim 11 wherein the rail and the recess is located intermediate twoend portions of the tab which are of substantially the same width as thewidth of the slot.
 13. A fin system according to claim 10 wherein thetab extends along the bottom surface of the fin from the leading edge toa point intermediate the leading and trailing edges of the fin.
 14. Afin system according to claim 10 wherein the tab extends along thebottom surface of the fin from the leading edge to approximately the midpoint between the leading and trailing edges of the fin.
 15. Areplaceable fin system for an aquafoil, comprising: a pot having a slottherein and adapted to be fitted into the surface of the aquafoil; afirst connection means extending into said slot; a fin having a leadingedge, a trailing edge, a base, a tab extending from the base away fromthe fin and adapted to fit within said slot, said tab extending alongthe base of the fin from adjacent the leading edge to end at a pointintermediate the leading and trailing edges; and a second connectionmeans located on said tab, which releasably engages with said firstconnection means to retain said tab in said slot; wherein said firstconnection means comprises two opposed arms, and the second connectionmeans comprises a bulbous projection located on a neck of the tab andthe two arms engage the neck behind the bulbous projection to abutagainst the bulbous projection to resist the vertical movement of thefin out of the slot, wherein the arms extend longitudinally along theslot and form a substantially c-shaped clamp in cross section and thebulbous projection is a rail extending longitudinally along the tab,with the neck being a longitudinally extending recess or recesseslocated between the rail and the base of the fin.
 16. A fin systemaccording to claim 15, wherein the rail and the recess or recesses arelocated intermediate two end portions of the tab, which are ofsubstantially the same width as the width of the slot.
 17. A method ofinstalling a pot for a replaceable fin system according to any one ofthe previous claims, the method comprising the steps of: markingaligning points on the aquafoil, for the fin position; positioning afirst jig having registration markings and a central cutout, such thatthe registration markings align with the registration points on theaquafoil and securing said first jig in position; routing out a cavitybounded by the periphery of the central cutout of the first jig;attaching one of said pots to a set up jig and positioning said setupjig on said first jig such that said pot is positioned within saidcavity; introducing a setting compound into said cavity around said potan allowing said setting compound to set to secure said pot in saidcavity; and removing said setup jig from said pot.
 18. A method ofinserting a pot for a replaceable fin system according to claim 17,wherein the registration markers are cross hair lines.
 19. A method ofinserting a pot for a replaceable fin system according to claim 17,wherein the opening of the pot cavity is bevelled.
 20. A method ofinserting a pot for a replaceable fin system according to claim 17,wherein the setting compound is a resin.